Light and circadian biology

Light has a profound effect on our physiology and behaviour in addition to it being necessary for vision.  Environmental light is crucial for synchronising our circadian clock to the 24-hour day and can also acutely impact our level of alertness, mood, and cognitive performance. 


We are concerned with developing and optimising lighting interventions for both working and clinical populations, to target the circadian clock and improve performance, safety, and quality of life. Through taking account of the characteristics of the specific photopigments in the eye that detect light for these responses, we are able to create dynamic lighting that changes in terms of brightness and colour across the course of the day to ensure the optimal effect. We also use mathematical models to understand how light interacts with circadian and sleep homeostatic mechanism.


Current research projects

Selected publications

Skeldon AC, Phillips AJ, Dijk DJ. The effects of self-selected light-dark cycles and social constraints on human sleep and circadian timing: a modeling approach. Sci Rep. 2017 Mar 27;7:45158. doi: 10.1038/srep45158. PMID: 28345624; PMCID: PMC5366875.

Santhi N, Groeger JA, Archer SN, Gimenez M, Schlangen LJ, Dijk DJ. Morning sleep inertia in alertness and performance: effect of cognitive domain and white light conditions. PLoS One. 2013 Nov 18;8(11):e79688. doi: 10.1371/journal.pone.0079688. PMID: 24260280; PMCID: PMC3832615.

Santhi N, Thorne HC, van der Veen DR, Johnsen S, Mills SL, Hommes V, Schlangen LJ, Archer SN, Dijk DJ. The spectral composition of evening light and individual differences in the suppression of melatonin and delay of sleep in humans. J Pineal Res. 2012 Aug;53(1):47-59. doi: 10.1111/j.1600-079X.2011.00970.x. Epub 2011 Oct 24. PMID: 22017511.

View all our selected publications